JPS6072762A - Paper feed tractor for printer - Google Patents

Abstract

PURPOSE:To enable easy fixing of two sprocket wheels at a specified position according to the paper width by change the outer diameter of an angular shaft of a paper feed tractor. CONSTITUTION:A dovetail-shaped thread 21 and a dovetail groove-shaped recessed groove 22 are provided respectiviely on the contact surfaces between fixed wedge-shaped sections 19a and 19b and mobile wedge-shaped sections 20a and 20b of an angular shaft 11 of a paper feed tractor. The mobile wedge- shaped sections 20a and 20b is slidable along the length of the angular shaft 11 by fitting them together. When operation knobs 24 and 24 in operation mechanisms 14 and 14 are loosed to slide the mobile wedge-shaped sections separately in the directions B and D, the outer diameter (d) of the angular shaft 11 reduces. Under such a condition, sprocket wheels 12 and 12 are slid over the circumferential surface of the angular shaft and stopped at the position according to the width of a paper. Then, the operation knob is reversed to increase the outer diameter (d) of the angular shaft 11 and the position of the sprocket wheels are fixed.

Description

Detailed Description of the Invention (1) Technical Field of the Invention The present invention relates to a paper feed retractor for a printer that prints output results from a computer, etc., and particularly relates to a paper feed retractor for a printer that prints output results from a computer, etc. This invention relates to a paper feed tractor for a printer that prevents printing misalignment.

Q) Prior Art and Problems As shown in FIGS. 1 and 2, this type of conventional paper feed retractor has an outer circumferential surface of a square shaft 2 to which rotational force is transmitted by a drive gear 1 fixed to one end. Two sprocket wheels 4 having a square hole 3 in the center were slidably fitted at an appropriate interval l, and a pin belt 5 was wound around each of these sprocket wheels 4.4. In FIG. 1, the reference numeral 6 is a square hole bush that supports the square shaft 2, and the reference numeral T is a bearing for the square shaft 2 and the square hole bush 6. The reference numeral 8 is a side frame. Then, for example, the computer paper is set by fitting sprocket holes drilled on both sides of the computer paper into a number of bins 9.9 protruding from the outer peripheral surface of the pin belt 5. When the drive gear 1 is rotationally driven by a motor (not shown), the computer paper is fed in a predetermined direction.

However, in this case, it is necessary to slide the two sprocket wheels 4.4 in the longitudinal direction of the square shaft 2 and adjust the distance l between them as appropriate, depending on the paper width of the paper. The inner diameter of the square hole 3 was slightly larger than the outer diameter d of the square shaft 2. Therefore, the square shaft 2 and the sprocket wheel 4
It was inevitable that there would be some rift between them.

Particularly in recent years, with the improvement in the functionality of printers, graphic printing of figures on paper is performed, but in this case, the paper is frequently fed in the forward direction and in the reverse direction. If there is any play between the square shaft 2 and the sprocket wheel 4 as described above when forward and reverse feeding returns to the base point where the figure, etc. However, printing misalignment occurred. Therefore, correct figures could not be drawn, and the positions of each digit in each print line did not match, resulting in a decrease in printing accuracy.

(3) Purpose of the Invention The present invention has been made to solve the above-mentioned problems, and is a printer that prevents print misalignment when printing by feeding paper 9 in the forward and reverse directions. The purpose is to provide a paper transport tractor.

(4) Structure of the invention and the above-mentioned object according to the present invention is to provide two sprocket wheels having a square hole in the center so as to be slidable at appropriate intervals on the outer peripheral surface of a square shaft to which rotational force is transmitted by a drive gear. In a paper feed tractor for a printer in which a bin belt is wound around each of these sprocket wheels, each part of the square shaft is divided into two wedge-shaped parts from the center to the opposite ends. A fixed wedge-shaped portion and a movable wedge-shaped portion are formed, and a protrusion and a groove are provided on the contact surfaces of the two members to enable sliding in the longitudinal direction of the two members when they are fitted together. This is achieved by providing a paper feed retractor for a printer, characterized in that operating mechanisms for sliding the movable wedge-shaped portions are provided at both ends thereof.

(5) Embodiments of the invention Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings.

The paper feed tractor of the printer according to the present invention has a unilateral shaft 11 and a sprocket wheel, as shown in FIG.
12, a bin belt 13, and an operating mechanism 14. The square shaft 11 rotates by being transmitted with rotational force by a drive gear 15 fixed to one end thereof, and is supported by bearings 17 and 17 provided at predetermined locations on the side frames 1B and 16. The reference numeral 18 is a square hole bushing for rotatably supporting the square shaft 11 on the bearings 17, 17.

As shown in FIG. 3, the square shaft 11 is divided into two wedge-shaped parts from the center toward both ends, and each part has a fixed wedge-shaped part l9a s.
19b and a movable wedge-shaped portion 20ax20b are respectively formed. And each fixed wedge-shaped part 19ax1
On the contact surface between 9b and the movable wedge-shaped portion 2Qas20b,
As shown in FIG. 4, a dovetail-shaped protrusion 21 and a dovetail-shaped recess #1J22 are provided respectively, and by fitting these together, the movable wedge-shaped portions 20a and 20b become square shafts. 11 is slidable along the longitudinal direction. Note that the protrusions 21 and grooves 22 do not necessarily have to be dovetail-shaped or dovetail-shaped, and may be, for example, normal convex or concave shapes.

At both ends of the square shaft 11, there are operating mechanisms 14.14.
is provided. The operating mechanism 14 is the movable wedge-shaped portion 201! Wedge-shaped part 1 fixing L%20 respectively
9a, 19bK& arrows A, B; It slides like a CSD, and consists of an operating knob 24 screwed into the ends 23ax23b of the fixed wedge-shaped parts 19a and 19b and a coil spring 25 to prevent loosening. .

The tip 2 of the screw shaft 26 of the operating knob 24 is
As shown in FIG. has been done. Therefore, the operation knob 24
When the screw shaft 26 is advanced in the direction of arrow a by rotation, the tip 2T of the screw shaft 26 pushes the inner wall of the hole 2B, causing the movable wedge-shaped portion 20a to slide in the direction of arrow A, and vice versa. When the screw shaft 26 is returned in the direction indicated by the arrow, the screw shaft 2
A nine E ring 29 provided at the tip 27 of the throat 3
0 to cause the movable wedge-shaped portion 20a to slide in the direction of arrow B. For this, square shaft 11
The outer diameter d can be changed as appropriate. The structure of the tip of the screw shaft 26 of the operating knob 24 is not limited to that shown in FIG. 5, and as shown in FIG. A tension spring 31 may be interposed between the tension springs 20a, and the elastic force of the tension spring 310 may be used to urge the constantly movable wedge-shaped portion 20a in the direction of arrow B.

As shown in FIG. 3, the square shaft 11 is provided with two sprocket wheels 12, 12 at an appropriate interval l. This sprocket wheel 12.12 is
It drives a bin belt 13, which will be described later, and connects a square hole 32 (see FIG. 4) formed in its center to the square shaft 1.
By fitting into the outer peripheral surface of the square shaft 11, it rotates together with the rotation of the square shaft 11.

The two sprocket wheels 12.12 are capable of sliding in the longitudinal direction of the square shaft 11, and the distance l between them is adjusted according to the width of the paper to be printed.
You can do this by adjusting as appropriate.

Bin belts 13.13 are wound around the outer peripheries of the two sprocket wheels 12.12, respectively. This bin bell) 13.13 is for directly conveying the paper to be printed, such as computer paper, and the outer peripheral surface of the bin bell) 13.13 has bins 33.33 and 33. A large number of... are highlighted.

In order to adjust the distance between the two sprocket wheels 12, 12 according to the paper width of the paper to be printed on in the printer's paper feed 9 tractor configured in this way, first, the operation mechanism at both ends of the square shaft 11 is adjusted. Loosen the operating knobs 24 and 14 and slide the movable wedge-shaped parts 20a and 20b outward in the direction of arrows B and D, respectively.

At this time, the outer diameter d of the square shaft 11 becomes smaller due to the tapered contact between the fixed wedge-shaped parts 19a, 19b and the movable wedge-shaped parts 20a, 20, and 20b. In this state, each of the sprocket wheels 12, 12 is appropriately slid on the outer circumferential surface of the square shaft 11, and stopped at a position corresponding to the paper width of the paper. Next, the operating knobs 24, 24 are turned in the opposite direction and screwed in, and the movable wedge-shaped parts 20a, 20b are slid inward as shown by arrows A and C, respectively. Then, due to the tapered contact between the fixed wedge-shaped parts 19a, 19b and the movable wedge-shaped parts 20a, 20b, the outer diameter d of the square shaft 11 increases. Since the outer diameter d of the square shaft 11 increases in this way, the outer peripheral surface of the square shaft 11 strongly contacts the inner peripheral surface of the square hole 32 of the sprocket wheel 12.12, thereby changing the position of the sprocket wheel 12.12. is fixed. At the same time, play between the square shaft 11 and the square hole 32 of the sprocket wheel 12.12 is also removed.

(6) Effects of the invention Since the present invention is configured as described above, the square shaft 11
By operating the operating mechanisms 14.14 at both ends of the
The outer diameter d of the square shaft 11 can be changed as appropriate. Therefore, the two sprocket wheels 12.1
When adjusting the interval j of 2 according to the paper width, the outer diameter d is made smaller and the sprocket wheel 12.12
The sprocket wheels 12 and 12 can be slid smoothly, and when the sprocket wheels 12 and 12 are stopped at a predetermined position, the outer diameter d can be increased to securely fix the sprocket wheels 12 and 12.

At the same time, the play between the square shaft 11 and the square hole 32 of the sprocket wheel 12.12 is also removed, so that the paper is not frequently fed in the forward or reverse direction, for example, in graphic printing where figures are drawn on the paper. Even if the printing is repeated repeatedly, so-called backlash does not occur, and printing misalignment can be prevented from occurring.

Therefore, correct figures can be drawn in graphic printing, and the positions of each digit in each printing line can be matched even in forward and reverse printing, and printing accuracy can be improved.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional explanatory diagram showing a paper feed tractor of a conventional printer, FIG. 2 is a cross-sectional view taken along line nn in FIG. 1, and FIG. 3 is a partial cross-sectional view showing a paper feed tractor of a printer according to the present invention. 4 is a sectional view taken along the line 0N-T in FIG. 3, FIG. 5 is an enlarged explanatory view of the main part showing the operating mechanism, and FIG. 6 is an enlarged main part showing a modification of the operating mechanism. It is an explanatory diagram. 11... Square shaft 12... Sprocket wheel 13...
・Bin belt 14...Operating mechanism 15...Drive gear 16...Side frame 1T...Bearings 19a, 19b...Fixed wedge-shaped portion 20a, 2
0tl...Movable wedge-shaped portion 21...Protrusion 22...Concave groove 24...Repetition knob 25...Coil spring 32 ... Square hole d ... Outer diameter of square shaft l ... Distance between sprocket wheels Applicant
Fujitsu Limited Agent Patent Attorney Koji Matsuoka #□゛ - ( (13) Figure 1 Figure 2

Claims (1)

[Claims] Two sprocket wheels with a square hole in the center are slidably fitted at appropriate intervals on the outer peripheral surface of a square shaft to which rotational force is transmitted by a drive gear, and a bin belt is wound around each of these sprocket wheels. In a paper feed retractor for a printer, the square shaft is divided into two wedge-shaped parts toward both ends with the center as a boundary, forming a fixed wedge-shaped part and a movable wedge-shaped part, and Protrusions and grooves are provided on the contact surfaces of the members to enable sliding in the longitudinal direction when these are fitted, and operating mechanisms for sliding the movable wedge-shaped portions are provided at both ends of the square shaft. A paper feed retractor for a printer, characterized in that: